Operating mechanism for spray guns



June 19, 1951 e. E. BJORKMAN OPERATING MECHANISM FOR SPRAY suns Filed Nov. 28, 1945 GIASMI/EEEIK m MK. PM

Patented June 19, 1951 2,557,593 OPERATING MECHANISM FOR SPRAY GUNS Gustaf Erik Bjiirkman, Stockholm, Sweden, as-

signor to Aktiebolaget Atlas Diesel, Sickla, near Stockholm, Sweden, a corporation of Sweden Application November 28,1945, Serial No. 631,317

In-Sweden April 26, 1944 6 Claims. (Cl. 299-140) This invention relates to operating mechanism for spray guns of the type in which a spray stream of a material is obtained with the aid of a pressure medium and which comprises a gun body accommodatin a discharge valve controlling spindle and a trigger for operating said spindle.

A principal object of the invention is to provide new and improved means for adjustably limiting the trigger movement to thereby control the movement of the valve spindle, the movement of which in turn controls the quantity of the material discharged by the gun. Another object is to provide new and improved means for tightening the packing around the valve spindle to prevent leakage of the material to be sprayed.

Other features of the invention together with the advantages to be derived from its use, will be apparent from the ensuing portion of this specification, taken in conjunction with the accompanying drawing.

In the accompanying drawing one embodiment of a spray gun for spraying paint or the like is illustrated by way of example it being understood,

however, that the invention is not limited to paint spray guns but may be employed in spray guns for other liquids or materials in which the 2 to which spraying material is admitted and rearwardly in the gun body and has a sleeve '9 secured on its rear end. Said sleeve is adjustable on the valve spindle in its axial direction and forms a seat and guiding means for :a spring I serving to press the valve spindle towards closed position. The rear end of said spring is seated in 1 a pocket II in the cover I. The valve spindle 1 extend-s through a transverse wall in the gun spraying material is sprayed with the aid of a pressure medium such as compressed air or the like.

In the drawing Fig. 1 is a side elevation and I partial section of a spray gun, Fig. 2 a partial tends downwardly substantially perpendicularly to the gun body. At the front end of the gun body a spray head 3 is provided, which maybe of any form common to the art having discharge openings for the spraying material and the pressure medium. The rear portion of the gun body I and the upper rear portion of the handle 2 form a removable cover 4, which covers the mechanism for controlling the spraying material and the pressure medium such as compressed air. Underneath the front portion of the gun body a bracket 5 is formed which carries a container 6 for spraying material.

In order to control the discharge of sprayin material from the spray gun a needle valve is provided in the gun body, the valve spindle 1 of which is axially displaceable in the gun body I. The valve spindle 1 extends through a space 8 body, which accommodates a packing l2 surrounding the, valve spindle. This packing may be tightened by means of a hollow threaded packing screw [3 and prevents spraying material from leaking out around the valve spindle from the space *8. The packing screw I3 is screwed into a bushing [4 provided in the rear wall of the space l5 to which compressed air is admitted and from which preferably valve controlled ducts 16 lead to the spray head and the air nozzles arranged therein. I The packing screw l3 has an extension at the rear end, which has hexagonal external cross section and forms a guiding means for a sleeve II, which has a corresponding hexagonal internal section as obvious from Fig. 2.

A trigger is is journalled at the upper end in the top of the gun body. A sleeve l9 secured on the sleeve I1 forms together with the sleeve 9 an intermediate member, which is slideable in the axial direction of the gun body and the valve spindle 1, and which is guided on the extension of the packing screw l3, and which upon a certain displacement of the trigger rearwardly in the gun body from the position illustrated in the drawing abuts the inner end flange of the sleeve 9 and upon further movement rearwardly of the trigger displaces thevalve spindle 7. When the sleeve I9 is turned clockwise the packing screw I3 is screwed into the bushing l4 and the packing l2 tightened. A trigger stop 20 is adjustable in the axial direction of the valve spindle 1 by means of an adjusting nut '2l which is rotatable in the gun body but which vis prevented from displacement in axial direction of the gun body by engaging the transverse walls 40, 4| of openings in the side walls 36 of the gun body defined by walls 35 and said walls 46, 6|. The adjusting nut 2| is screw-threaded on the trigger stop 20 which is secured against rotation by means of projections 31 engaging corresponding longitudinal grooves 38 in the trigger stop 25 to guide the stop when it is axially adjusted. The stop 20 may also be prevented from turning by other means, for instance by the provision of a forked extension at the front end of the stop embracing the trigger IS. The leeve 20 forms an abutment for thetrigstream' of a material-is discharged atone endOf ger I'8, which limits the backward movement of the trigger.

In Fig. 1 the stop 20 is illustrated in its extreme forward position, in which movement of the trigger is prevented so that paint and air dis- 5 charge through the spray head nozzles is prevented. The trigger l8 extends onboth sides of the sleeve IT with branches forming "camsurfaces 39 on the rear side thereof engaging the front end of the sleeve [9.

In the rear portion of the gun bodyabellcrank member 22 is journalled on a pin extending transversely to the longitudinal.centrevplane -of-'-the spray gun. One arm of said-1 bellcranlcrmember engages a flange formed atf therear endof 'the l5 sleeve 19 and the other arm astem .23. disposed and displaceable lengthwise of the handle]. Z'Ihe lower portion of the handle 2 is provided with a hose connection 24 for an air hose. "Aduct' in the hose connection 24 communicates with a space -25 :in the handle 2 accommodating a-ballvalve 26. The ball valve may be opened by pushing the stem'23 downwardly in the handle and wiszclosed why acspring Zl'and the air pressure. -A-duct-28 ileads from the space 25 to a space Raina-their rhand'le 2, from which ducts 39 lead to the space l5iin the gun'body. Furthermore a duct' 32"contI'OIIBdby aball valve3l leads to the spray 'marterial'container 6 which-is thereby submittedzto pressure. The ball valve 3i is'loaded by aspring-auu "33 the'tension of which-may be adjusted 'bymeans ebfia set screw 34.

"Foryoperation'of the spray gun thev adjusting 'Ynut 2|, which projects through the'openings *in thezside walls 36 of the gun body I, is iturnedwals:

r'so'that the stop 20 is displaced rearwardly'in the r"gun;body. thereby permitting the trigger to'move 11a corresponding 'distance towards the handle: 2. -"When the trigger I8 is pressed towards thehan- 'rearwardlyin the gun body causing thebell crank member 22 to swing backwardly and downwardly sand toipushthe stem 23 towards theball valve 26 so that compressed air is admitted to the spray ahead and the spraying material container. ,Upon i'further' movement of the trigger 18 in the same odirection the valve spindle I is displaced ba'ck- :wardly' in the gun body by the sleeve ILnwhich *engages the inner end of the sleeve 9. Spray- .iringrm'aterial. and compressed air are thenrdis- ":charged' through the spray head of the gun. -tThrough adjustment of the nut'2l..the opening .'movement of the trigger is limited and. consequentl also the quantity of spraying. material ":whichlis"discharged through the. spray head. v

-:Through adjustment of the tension of .the spring 'L- 331 bymeans of the screw 34 the pressure on'the r spraying' material in the container -6 smay t-be avaried. .The air supply to the difierent air noz- TJZlBSiiIl the spray head may be furthercontrolled 50 .vbyvalves 01' the like in the air ducts to-and in 1the'spray head in a manner known per se in the art.

The spray gun above described should only 'be modified in several different ways within the scope of the claims. For instance, the stem '23 may be of adjustable length, 'Apressure reduc- 'tion valve may be provided in the duct 16. Compressed gas or other suitable pressure mediums. "may be used instead of compressedair.

What I claim is: 1.In a spray gun of the type in which a spray a'gunbody; a spray headat the discharge-end .eningsaidpacking, and an extension on said of the gun body, a material discharge valve spindle extending and displaceable in the gun body, a. trigger, a rotatable intermediate sleeve member disposed coaxially with said valve spindle and operably cooperating with said trigger to move in the axial direction of the valve spindle relaqiptive to the 'gun' bodyand the valve spindle upon lzmovement of the trigger,--a packing surrounding the valve spindle in the gun body, a packing screw coaxial with the valve spindle for tightpacking screw forming guiding means for said 1: intermediate sleeve member coaxial with the 'valve 'spindle'and'cooperating with the intermediate member to'permit displacement of the intermediate member in the axial direction of the valve spindle relative to said extension but preventing rotation of the intermediate member relative to the extension.

2. In a spray gun of the type in which a spray "stream of amaterial and'a pressure medium are dischargedat oneend-.of a 'gun body," aspray head at 'thedischarge end of the gun body; amateri'a-ldischarge valve spindle extending and'idisplaceable in the gun bodyy a trigger, an inter- -mediate member disposed coaxially withbaid valve spindle and operably cooperating with said triggerto move in the axial direction of "the valve spindle relative to the-gun body and the' valve spindle upon-movement ofthe trigger; a trigger :stopcoaxial with thevalvespindle, said trigger stop forming a guidefor said intermediate member and permitting rotational and axial-displacement' of'the intermediate member relative to said stop and-"forming anabutment. for' limiting the movement of the trigger,=means for preventing rotational movement of-the stop and permitting displacement of the stop in "the axial direction "of the valve spindleg-anadjusting nut "screw- C'dlEthB intermediate member 11,19 is .displacediioi threaded on the stop to be rotatable with respect to the gun body but prevented fromdisplacemcnt in 'the' axial direction of the valve spindle-and accessible for manipulation from the exterior-of the gun body, an'abutment'on the valve spindle disposed in the path of the intermediate'member soas 'to be displaced uponmovement'of the trigger and the intermediate member, and a-p'ressure medium control valve operated to admit pressure medium to the gun'body uponmovement of .trigger stop for limiting'the 'movementof the trigger rearwardly in the gun body, said trigger stop being displaceable in the direction of-moveamentof the spindle-but lockedagainst rotationin "the gun body,.and means for adjusting said stop,

said adjusting means: being accessible from the outside of the: gun bodyand engaging said stop L for moving the' stop and for holding thestop in positionsof adjustmentpsaid means being'rotatxb wonsidered as anexample and may naturally 65 iablefill gun bo y b t locked ae p 'mentiinthe direction of' movement of the spindle isinithe-gunbody.

'14. A spray gun having a gun body-and a valve controlled spray material' nozz1e, -a' 'noz?z1e valve controlling spindle movable in said gun' body,- a

trigger operably combined-with said spindle for moving the spindle; an adjustabletriggerstop-for limiting' themovement or the trigger re arwar'dly i in the gun :body; said-triggerstop being-displaceable ;in':the: direction of movement: of-the spindle but locked against rotation in the gun body, external screw threads on the trigger stop, and means for adjusting said stop, said adjusting means being accessible from the outside of the gun body and provided with screw threads engaging said screw threads on the stop for moving the stop and for holding the stop in positions of adjustment, said adjusting means furthermore being rotatable in the gun body but locked against displacement in the direction of movement of the spindle in the gun body.

5. A spray gun having a gun body and a valve controlled material discharge nozzle, a nozzle valve controlling spindle movable in said gun body, a trigger operably combined with said spindle for moving the spindle, an adjustable trigger stop for limiting the movement of the trigger rearwardly in the gun body, means for guiding said stop in the gun body to permit displacement of the stop in the direction of movement of the spindle but to prevent turning of the stop in the gun body, and means for adjusting said stop, said adjusting means being accessible from the outside of the gun body and engaging the stop for moving the stop in said guiding means and for holding the stop in positions of adjustment, said adjusting means furthermore being rotatable in the gun body but locked a ainst displacement in the direction of movement of the spindle in the gun body.

6. A spray gun having a gun body and a valve controlled material discharge nozzle, a nozzle valve controlling spindle movable in said gun body, a trigger, an adjustable trigger stop of sleeve-like form for limiting the movement of the trigger rearwardly in the gun body, means for adjusting and engaging said stop, said adjustable means being accessible from the outside of the gun body for moving and holding the stop in positions of adjustment in the gun body, an intermediate member guided coaxially with the valve spindle in the stop and operably cooperating with said trigger to move in the direction of the valve spindle relative to the stop and the valve spindle upon movement of the trigger, an abutment on the valve spindle disposed in the path of said intermediate member so as to be displaced upon movement of the trigger and the intermediate member, and a separate pressure medium control valve operably cooperating with the intermediate member so as to be opened upon movement of the trigger and the intermediate member.

GUSTAF ERIK BJRKMAN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,650,686 Binks Nov. 29, 1927 1,689,848 Anderson Oct. 30, 1928 1,698,945 Driscoll Jan. 15, 1929 1,762,282 Stephan June 10, 1930 1,797,209 Bramsen et a1. Mar. 17, 1931 1,802,141 Downs Apr. 21, 1931 1,940,268 Peterson Dec. 19, 1933 1,958,730 Tracy May 15, 1934 1,980,464 Yedd Nov. 13, 1934 1,981,077 Shields Nov. 20, 1934 1,987,248 Seizer Jan. 8, 1935 2,005,776 Downs June 25, 1935 2,027,103 Johnson et a1. Jan. 7, 1936 2,096,196 Newlin Oct. 19, 1937 2,149,932 Zippel Mar. 7, 1939 2,152,767 McKnight Apr. 4, 1939 Certificate of Correction Patent No. 2,557,593 June 19, 1951 GUSTAF ERIK BJORKMAN It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows:

Column 2, line 55, for sleeve read stop; column 5, lines 37 and 38, for adjustable read adjusting;

and that the said Letters Patent should be read as corrected above, so that the same may conform to the record of the case in the Patent Office. Signed and sealed this 11th day of September, A. D. 1951.

[SEAL] THOMAS F. MURPHY,

Assistant Commissioner of Patents. 

